Zoom lens

ABSTRACT

The present disclosure relates to optical lens, and provides a zoom lens including, from an object side to an image side in sequence: a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, a fifth lens group having a negative refractive power; distances between adjacent two of the first lens, the second lens, the third lens, the fourth lens and the fifth lens group are variable in the direction of the optical axis; the fifth lens group including a fifth lens having a positive refractive power and a sixth lens having a negative refractive power; wherein the zoom lens satisfies conditions of: f_Tele/f_Wide&gt;1.8; −1.85≤f3/f2≤−1.20; and 2.00≤f4/f2≤3.00.

TECHNICAL FIELD

The present disclosure relates to a zoom lens which has a telescoping structure, particularly, to a zoom lens which is suitable for a smart phone or a camera using imaging elements such as Charge Coupled Device (CCD) or Complementary Metal-Oxide Semiconductor Sensor (CMOS sensor) for high pixels, and the like, and which becomes bright and has excellent optical performance when an F number (“Fno” hereinafter) is less than 2 at the wide angle end, which become miniature when a zoom ratio is more than 1.8 and a total track length (TTL) is less than 9.00 mm when contracted, and which includes five groups of lenses having six lenses.

BACKGROUND

In recent years, a zoom lens has been sought which has an Fno of less than 2 at the wide angle end, has a zoom ratio of more than 2.0 and excellent optical performance, and which becomes miniature when a barrel is contracted into the camera to reduce the TTL at the time of non-shooting.

A development for a zoom lens having six lenses is being advanced. As the zoom lens which includes six lenses, a lens which consists of three groups having six lenses is proposed in the US Patent Publication No. US2020/0241265A1 (Patent Document 1 hereinafter).

In the camera optical lens disclosed in Embodiments of Patent Document 1, a zoom ratio is more than 4.74. However, when the Fno is more than 2.552, the camera optical lens has insufficient brightness, and TTL is long when shooting and miniaturization thereof is insufficient.

SUMMARY

An objective of the present disclosure is to provide a zoom lens which has TTL of less than 9.00 mm and becomes miniature when contracted, which becomes bright when an Fno at the wide angle end is of less than 2.0 at the time of photographing, which has excellent optical performance and a zoom ratio of more than 1.8, and which includes five groups of lenses having six lenses.

In order to achieve the above objective, the inventor conceived in the present disclosure a zoom lens capable of solving the problem in the existing technology, by studying a ratio of a focal length of the third lens to a focal length of the second lens, a ratio of a focal length of the fourth lens to a focal length of the second lens.

To solve the above technical problem, embodiments of the present disclosure provide a zoom lens. The zoom lens includes, from an object side to an image side in sequence: a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, a fifth lens group having a negative refractive power; distances between adjacent two of the first lens, the second lens, the third lens, the fourth lens and the fifth lens group are variable in the direction of an optical axis; the fifth lens group includes a fifth lens having a positive refractive power and a sixth lens having a negative refractive power; and the zoom lens satisfies conditions of: f_Tele/f_Wide>1.8 (1); −1.85≤f3/f2≤−1.20 (2); and 2.00≤f4/f2≤3.00 (3); where f_Wide denotes a focal length of the zoom lens at the wide angle end; f_Tele denotes a focal length of the zoom lens at the telephoto end; f2 denotes a focal length of the second lens; f3 denotes a focal length of the third lens; f4 denotes a focal length of the fourth lens.

As an improvement, the zoom lens further satisfies a condition of: −3.20≤f1/f2≤−2.50 (4); where f1 denotes a focal length of the first lens, and f2 denotes a focal length of the second lens.

As an improvement, the zoom lens further satisfies a condition of: −5.00≤fG5/f2≤−2.50 (5); −3.10≤f5/f6≤−2.00 (6); where f2 denotes a focal length of the second lens; fG5 denotes a combined focal length of the fifth lens group; f5 denotes a focal length of the fifth lens; f6 denotes a focal length of the sixth lens.

As an improvement, the zoom lens further satisfies a condition of: 4.78≤LB_Tele/LB_Wide≤6.20 (7); where LB_Wide denotes an on-axis distance from an image-side surface of the sixth lens to an image surface at the wide angel end; LB_Tele denotes an on-axis distance from an image-side surface of the sixth lens to an image surface at the telephoto end.

As an improvement, the zoom lens further satisfies a condition of: 76.00≤v1≤82.00 (8); 58.00≤v2≤78.00 (9); 76.00≤v6≤82.00 (10); where v1 denotes an abbe number of the first lens L1; v2 denotes an abbe number of the second lens L2; v6 denotes an abbe number of the sixth lens L6.

The present disclosure is advantageous in follows.

According to the present disclosure, the zoom lens is provided, which is suitable for a camera module of a smart phone or a WEB camera using imaging elements such as Charge Coupled Device (CCD) or Complementary Metal-Oxide Semiconductor Sensor (CMOS sensor) for high pixels, and the like, and which has TTL of less than 9.00 mm and becomes miniature when contracted, which has Fno of less than 2.0, a zoom ratio of more than 1.8 and excellent optical performance and becomes bright, and which includes five groups of lenses having six lenses.

BRIEF DESCRIPTION OF DRAWINGS

To illustrate the technical solutions according to the embodiments of the present disclosure or in the prior art more clearly, the accompanying drawings for describing the embodiments or the prior art are introduced briefly in the following. Apparently, the accompanying drawings in the following description are only some embodiments of the present disclosure, and persons of ordinary skill in the art can derive other drawings from the accompanying drawings without creative efforts.

FIG. 1 is a schematic diagram of a structure of a zoom lens LA according to Embodiment 1 of the present disclosure.

FIG. 2 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 1 of the present disclosure.

FIG. 3 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 1 of the present disclosure.

FIG. 4 is a schematic diagram of a structure of a zoom lens LA according to Embodiment 2 of the present disclosure.

FIG. 5 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 2 of the present disclosure.

FIG. 6 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 2 of the present disclosure.

FIG. 7 is a schematic diagram of a structure of a zoom lens LA according to Embodiment 3 of the present disclosure.

FIG. 8 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 3 of the present disclosure.

FIG. 9 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 3 of the present disclosure.

FIG. 10 is a schematic diagram of a structure of a zoom lens LA according to Embodiment 4 of the present disclosure.

FIG. 11 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 4 of the present disclosure.

FIG. 12 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 4 of the present disclosure.

FIG. 13 is a schematic diagram of a structure of a zoom lens LA according to Embodiment 5 of the present disclosure.

FIG. 14 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 5 of the present disclosure.

FIG. 15 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 5 of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of the present disclosure clearer, embodiments of the present disclosure are described in detail with reference to accompanying drawings in the following. A person of ordinary skill in the art can understand that, in the embodiments of the present disclosure, many technical details are provided to make readers better understand the present disclosure. However, even without these technical details and any changes and modifications based on the following embodiments, technical solutions required to be protected by the present disclosure can be implemented.

Embodiments of a zoom lens in the present disclosure will be described. The zoom lens is a lens system which includes five groups of lenses having six lenses. The lens system includes, from an object side to an image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens group G5, where the fifth lens group includes a fifth lens L5 and a sixth lens L6. A glass plate GF is disposed between the sixth lens L6 and an image surface Si. The glass plate GF may include glass cover plates, various filters, and the like. In the present disclosure, the glass plate GF may be disposed at different positions or may be omitted.

In this embodiment, the first lens L1 has a negative refractive power, the second lens L2 has a positive refractive power, the third lens L3 has a negative refractive power, the fourth lens L4 has a positive refractive power, and the fifth lens group G5 has a negative refractive power. The fifth lens group G5 includes the fifth lens L5 and the sixth lens L6, where the fifth lens L5 has a positive refractive power, and the sixth lens L6 has a negative refractive power. For better correction to various distortions, all the surfaces of the six lenses are set as aspheric.

The zoom lens LA satisfies a condition of:

f_Tele/f_Wide>1.8  (1)

Condition (1) specifies a zoom ratio of the zoom lens LA. Within the condition (1), correction to various distortions is facilitated, and meanwhile the zoom ratio is sufficient.

The zoom lens LA satisfies a condition of:

−1.85≤f3/f2≤−1.20  (2)

Condition (2) specifies a ratio of a focal length f3 of the third lens L3 to a focal length f2 of the second lens L2. Within the condition (2), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom LA satisfies a condition of:

2.00≤f4/f2≤3.00  (3)

Condition (3) specifies a ratio of a focal length f4 of the fourth lens L4 to a focal length f2 of the second lens L2. Within the condition (3), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

−3.20≤f1/f2≤−2.50  (4)

Condition (4) specifies a ratio of a focal length f1 of the first lens L1 to a focal length f2 of the second lens L2. Within the condition (4), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

−5.00≤fG5/f2≤−2.50  (5)

Condition (5) specifies a ratio of a combined focal length fG5 of the first lens L1 to a focal length f2 of the second lens L2. Within the condition (5), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom LA satisfies a condition of:

−3.10≤f5/f6≤−2.00  (6)

Condition (6) specifies a ratio of a focal length f5 of the fifth lens L5 to a focal length f6 of the six lens L6. Within the condition (6), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

4.78≤LB_Tele/LB_Wide≤6.20  (7)

Condition (7) specifies a ratio of an on-axis distance from an image-side surface of the sixth lens to an image surface at the telephoto end to an on-axis distance from an image-side surface of the sixth lens to an image surface at the wide angel end. Within the condition (7), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

76.00≤v1≤82.00  (8)

Condition (8) specifies an abbe number of the first lens L1. Within the condition (8), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

58.00≤v2≤78.00  (9)

Condition (9) specifies an abbe number of the first lens L1. Within the condition (9), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

The zoom lens LA satisfies a condition of:

76.00≤v6≤82.00  (10)

Condition (10) specifies an abbe number of the first lens L1. Within the condition (10), miniaturization when contracted is facilitated, and meanwhile correction to various distortions is facilitated when Fno is less than 2.0 and the zoom ratio is more than 1.8 at the wide angle end.

With the five groups of lenses having six lenses included in the zoo lens LA satisfying the above structure and conditions respectively, the zoom lens LA is obtained which has TTL of less than 9.00 mm and becomes miniature when contracted, which has Fno of less than 2.0, a zoom ratio of more than 1.8 and an excellent optical performance and becomes bright, and which includes five groups of lenses having six lenses.

Embodiments

The zoom lens LA will be further described with reference to the following examples. Symbols used in various examples are shown as follows. It should be noted that the distance, central curvature radius, and on-axis thickness are all in units of mm.

f: focal length of the zoom lens;

f1: focal length of the first lens L1;

f2: focal length of the second lens L2;

f3: focal length of the third lens L3;

f4: focal length of the fourth lens L4;

f5: focal length of the fifth lens L5;

f6: focal length of the sixth lens L6;

fG5: combined focal length of the fifth lens group G5;

FNO: ratio of an effective focal length and an entrance pupil diameter of the zoom lens;

2ω: full viewing angle;

STOP: aperture;

R: curvature radius of an optical surface (central curvature radius in the condition of the lens);

R1: central curvature radius of the object-side surface S1 of the first lens L1;

R2: central curvature radius of the image-side surface S2 of the first lens L1;

R3: central curvature radius of the object-side surface S3 of the second lens L2;

R4: central curvature radius of the image-side surface S4 of the second lens L2;

R5: central curvature radius of the object-side surface S5 of the third lens L3;

R6: central curvature radius of the image-side surface S6 of the third lens L3;

R7: central curvature radius of the object-side surface S7 of the fourth lens L4;

R8: central curvature radius of the image-side surface S8 of the fourth lens L4;

R9: central curvature radius of the object-side surface S9 of the fifth lens L5;

R10: central curvature radius of the image-side surface S10 of the fifth lens L5;

R11: central curvature radius of the object-side surface S11 of the sixth lens L6;

R12: central curvature radius of the image-side surface S12 of the sixth lens L6;

R13: central curvature radius of an object-side surface S13 of the glass plate GF;

R14: central curvature radius of an image-side surface S14 of the glass plate GF;

d: on-axis thickness of a lens or an on-axis distance between lenses;

d1: on-axis thickness of the first lens L1;

D12: on-axis distance from the image-side surface S2 of the first lens L1 to the object-side surface S3 of the second lens L2;

d2: on-axis distance from the image-side surface S2 of the first lens L1 to the aperture STOP;

d3: on-axis distance from the aperture STOP to the object-side surface S3 of the second lens L2;

d4: on-axis thickness of the second lens L2;

d5: on-axis distance from the image-side surface S4 of the second lens L2 to the object-side surface S5 of the third lens L3;

d6: on-axis thickness of the third lens L3;

d7: on-axis distance from the image-side surface S6 of the third lens L3 to the object-side surface S7 of the fourth lens L4;

d8: on-axis thickness of the fourth lens L4;

d9: on-axis distance from the image-side surface S8 of the fourth lens L4 to the object-side surface S9 of the fifth lens L5;

d10: on-axis thickness of the fifth lens L5;

d11: on-axis distance from the image-side surface S10 of the fifth lens L5 to the object-side surface S11 of the sixth lens L6;

d12: on-axis thickness of the sixth lens L6;

d13: on-axis distance from the image-side surface S12 of the sixth lens L6 to the object-side surface S13 of the glass plate GF;

d14: on-axis thickness of the glass plate GF;

d15: on-axis distance from the image-side surface S14 of the glass plate GF to the object-side surface S15 of the image surface;

nd: refractive index of the d line;

nd1: refractive index of the d line of the first lens L1;

nd2: refractive index of the d line of the second lens L2;

nd3: refractive index of the d line of the third lens L3;

nd4: refractive index of the d line of the fourth lens L4;

nd5: refractive index of the d line of the fifth lens L5;

nd6: refractive index of the d line of the sixth lens L6;

ndg: refractive index of the d line of the glass plate GF;

vd: abbe number;

v1: abbe number of the first lens L1;

v2: abbe number of the second lens L2;

v3: abbe number of the third lens L3;

v4: abbe number of the fourth lens L4;

v5: abbe number of the fifth lens L5;

v6: abbe number of the sixth lens L6;

vg: abbe number of the glass plate GF;

TTL: Total optical length (on-axis distance from the object side surface S1 of the first lens L1 to the image surface of the zoom lens) in mm;

LB: on-axis distance from the image-side surface S12 of the sixth lens L6 to the image surface.

Embodiment 1

FIG. 1 is a schematic diagram of a structure of the zoom LA according to Embodiment 1 of the present disclosure. Table 1 shows the central curvature radiuses R of the object-side surfaces and the image-side surfaces of the zoom lens LA of the first lens L1 to the six lens L6, the on-axis thicknesses d of the lenses, the on-axis distances d between the lenses, the refractive indexes nd and the abbe numbers vd. Table 2 shows the values of A, B, C, D and E when contracted or photographing. Table 3 shows the conic coefficient k and the aspheric surface coefficients. Table 4 shows values of Fno, 2ω, f, TTL, LB, f1, f2, f3, f4, fG5, f5, f6, IH and zoom ratio.

The design data of the zoom LA in Embodiment 1 of the present disclosure are shown in Table 1.

TABLE 1 effective R d nd νd radius (mm) S1 R1 9.61540 d1 0.848 nd1 1.4959 ν1 81.655 4.789 S2 R2 4.78994 D12 d2 A 4.201 Stop ∞ d3 −0.875  3.058 S3 R3 5.43455 d4 1.945 nd2 1.5806 ν2 60.079 3.085 S4 R4 −10.30283 d5 B 3.068 S5 R5 4.22326 d6 0.418 nd3 1.6700 ν3 19.392 2.804 S6 R6 2.37762 d7 C 2.792 S7 R7 −72.30089 d8 0.643 nd4 1.5438 ν4 56.029 2.792 S8 R8 −6.42171 d9 D 2.768 S9 R9 −422.21458 d10 0.687 nd5 1.6700 ν5 19.392 3.482 S10 R10 −16.16554 d11 0.050 3.599 S11 R11 6.61558 d12 0.507 nd6 1.4959 ν6 81.655 3.617 S12 R12 2.97312 d13 0.380 3.798 S13 R13 ∞ d14 0.210 ndg 1.5168 νg 64.167 3.868 S14 R14 ∞ d15 E 3.890 Reference wavelength = 587.6 nm

TABLE 2 Photographing Wide Tele Contracted A 6.374 1.150 1.075 B 1.292 1.087 0.200 C 1.511 2.391 0.654 D 4.498 0.200 0.200 E 1.114 9.960 0.890

TABLE 3 Conic coefficient Aspheric surface coefficients k A4 A6 A8 A10 S1 0.0000E+00 −3.7161E−03 2.1150E−04 −8.6464E−06  3.2195E−07 S2 0.0000E+00 −5.0043E−03 2.7486E−04 −2.2796E−05  1.9983E−06 S3 −4.1073E−01   4.8828E−04 −2.6565E−05   1.2402E−05 −2.4815E−06 S4 0.0000E+00  2.6570E−03 −5.5477E−05   7.0596E−06 −5.7191E−06 S5 0.0000E+00 −4.3942E−02 1.0026E−02 −2.0167E−03  2.9806E−04 S6 −4.1210E+00  −2.6213E−02 7.1515E−03 −1.6809E−03  2.8826E−04 S7 0.0000E+00 −3.2293E−03 8.8623E−04 −3.9750E−04  1.3776E−04 S8 2.1814E−01  1.7419E−03 3.3061E−04  5.2942E−05 −1.0663E−05 S9 0.0000E+00  9.8434E−03 −4.1050E−03   1.0649E−03 −1.7264E−04 S10 0.0000E+00  1.4996E−02 −7.5983E−03   2.0379E−03 −2.9367E−04 S11 −5.0000E+01  −1.8444E−02 5.4669E−04  6.5146E−04 −1.1815E−04 S12 −1.0143E+01  −1.4135E−02 2.5607E−03 −2.9863E−04  1.8766E−05 Conic coefficient Aspheric surface coefficients k A12 A14 A16 S1 0.0000E+00 −9.9365E−09 2.2247E−10 −2.7730E−12 S2 0.0000E+00 −1.4272E−07 6.0406E−09 −1.1574E−10 S3 −4.1073E−01   1.6043E−07 6.0347E−09 −9.7092E−10 S4 0.0000E+00  1.0816E−06 −8.7358E−08   2.3508E−09 S5 0.0000E+00 −2.9519E−05 1.6781E−06 −4.0053E−08 S6 −4.1210E+00  −3.2808E−05 2.1394E−06 −5.9001E−08 S7 0.0000E+00 −1.8645E−05 1.0372E−06 −1.9847E−08 S8 2.1814E−01  7.9451E−06 −1.2973E−06   5.9210E−08 S9 0.0000E+00  1.6328E−05 −8.4011E−07   1.8139E−08 S10 0.0000E+00  2.3324E−05 −9.9462E−07   1.8163E−08 S11 −5.0000E+01   8.3999E−06 −2.6527E−07   3.0971E−09 S12 −1.0143E+01  −6.0983E−07 9.6600E−09 −5.9281E−11

Herein, k denotes a conic coefficient, A4, A6, A8, A10, A12, A14, A16 denote aspheric surface coefficients.

y=(x ² /R)/[1+{1−(k+1)(x ² /R ²)}^(1/2)]+A4x ⁴ +A6x ⁶ +A8x ⁸ +A10x ¹⁰ +A12x ¹² +A14x ¹⁴ +A16x ¹⁶  (11)

Herein, x denotes a vertical distance between a point in the aspheric curve and the optical axis, and y denotes an aspheric depth (i.e. a vertical distance between the point having a distance of x from the optical axis and a plane tangent to the vertex on the optical axis of the aspheric surface).

For convenience, an aspheric surface of each lens surface uses the aspheric surfaces shown in the above formula (11). However, the present disclosure is not limited to the aspherical polynomials forms shown the formula (11).

TABLE 4 Wide Tele Fno 1.94 3.11 2ω (°) 46.96 24.13 f (mm) 9.252 18.503 Wide Tele Contracted TTL (mm) 19.600 19.600 7.831 LB (mm) 1.704 10.550 1.480 f1 (mm) −20.436 f2 (mm) 6.419 f3 (mm) −8.931 f4 (mm) 12.915 fG5 (mm) −22.052 f5 (mm) 25.069 f6 (mm) −11.415 IH (mm) 4.000 Zoom ratio 2.000

In the subsequent Table 21, various parameters of Embodiments 1, 2, 3, 4 and 5 and values corresponding to the parameters specified in the above conditions (1) to (10) are shown.

As shown in Table 21, Embodiment 1 satisfies the conditions (1) to (10).

FIG. 2 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 1 of the present disclosure. FIG. 3 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 1 of the present disclosure. It should be noted that a field curvature S is a field curvature in a sagittal direction, and T is a field curvature in a tangential direction which are also employed in embodiments 2, 3, 4, and 5. It can be known that the zoom lens becomes miniature with TTL equal to 7.831 and becomes bright with Fno equal to 1.94, and has a zoom ratio equal to 2.000 at the wide angle end and has excellent optical performance as shown in FIG. 2 and FIG. 3 in Embodiment 1 of the present disclosure.

Embodiment 2

FIG. 4 is a schematic diagram of a structure of the zoom LA according to Embodiment 2 of the present disclosure. Table 5 shows the central curvature radiuses R of the object-side surfaces and the image-side surfaces of the zoom lens LA of the first lens L1 to the six lens L6, the on-axis thicknesses d of the lenses, the on-axis distances d between the lenses, the refractive indexes nd and the abbe numbers vd. Table 6 shows the values of A, B, C, D and E when contracted or photographing. Table 7 shows the conic coefficient k and the aspheric surface coefficients. Table 8 shows values of Fno, 2ω, f, TTL, LB, f1, f2, f3, f4, fG5, f5, f6, IH and zoom ratio.

TABLE 5 effective R d nd νd radius (mm) S1 R1 11.54916 d1 0.980 nd1 1.4959 ν1 81.655 4.604 S2 R2 4.52385 D12 d2 A 3.947 Stop ∞ d3 −1.131  3.190 S3 R3 4.79882 d4 2.206 nd2 1.5806 ν2 60.079 3.202 S4 R4 −12.36368 d5 B 3.127 S5 R5 8.18784 d6 0.400 nd3 1.6700 ν3 19.392 2.689 S6 R6 3.84986 d7 C 2.500 S7 R7 8.58565 d8 0.770 nd4 1.5438 ν4 56.029 2.990 S8 R8 −65.64031 d9 D 3.025 S9 R9 −16.92466 d10 0.557 nd5 1.6700 ν5 19.392 3.481 S10 R10 −8.47675 d11 0.309 3.476 S11 R11 85.55021 d12 0.500 nd6 1.4959 ν6 81.655 3.705 S12 R12 4.55212 d13 0.340 3.741 S13 R13 ∞ d14 0.210 ndg 1.5168 νg 64.167 3.845 S14 R14 ∞ d15 E 3.871 Reference wavelength = 587.6 nm

TABLE 6 Photographing Wide Tele Contracted A 5.904 1.533 1.333 B 1.301 1.884 0.200 C 2.951 3.988 0.620 D 3.315 0.221 0.200 E 0.989 6.835 0.890

TABLE 7 Conic coefficient Aspheric surface coefficients k A4 A6 A8 A10 S1 0.0000E+00 −4.3273E−03 3.0195E−04 −1.3551E−05 3.9245E−07 S2 0.0000E+00 −6.2743E−03 3.7607E−04 −2.5241E−05 1.4655E−06 S3 −5.5335E−01   2.6661E−04 −2.7405E−05   1.8364E−05 −4.2766E−06  S4 0.0000E+00  1.3787E−03 1.5428E−04 −6.0202E−05 1.0644E−05 S5 0.0000E+00 −2.6907E−02 6.5909E−03 −1.3197E−03 2.1250E−04 S6 −3.8955E+00  −2.5433E−02 7.8649E−03 −1.9084E−03 3.7605E−04 S7 0.0000E+00 −3.6049E−03 −1.8631E−04  −7.8918E−05 2.1912E−05 S8 4.6350E+01 −2.9343E−04 −4.3523E−04   3.9347E−05 −1.0555E−05  S9 0.0000E+00  4.3758E−03 −1.5179E−03   1.7440E−04 3.8823E−06 S10 0.0000E+00  1.1313E−02 −3.6859E−03   4.3334E−04 8.7735E−06 S11 −4.3256E+01  −1.0058E−02 7.6167E−04 −4.6670E−04 1.6076E−04 S12 −1.5106E+01  −6.3607E−03 2.8458E−04 −1.8017E−05 1.1228E−05 Conic coefficient Aspheric surface coefficients k A12 A14 A16 S1 0.0000E+00 −4.3114E−09 −9.6807E−11   2.4063E−12 S2 0.0000E+00 −9.2753E−08 4.2407E−09 −1.0222E−10 S3 −5.5335E−01   5.2175E−07 −3.1865E−08   7.6092E−10 S4 0.0000E+00 −1.0830E−06 5.9866E−08 −1.4064E−09 S5 0.0000E+00 −2.3490E−05 1.5289E−06 −4.3300E−08 S6 −3.8955E+00  −5.0004E−05 3.8761E−06 −1.2844E−07 S7 0.0000E+00 −3.5289E−06 3.3353E−07 −1.0855E−08 S8 4.6350E+01  1.8938E−06 −1.5287E−07   6.3304E−09 S9 0.0000E+00 −1.9526E−06 1.1519E−07 −1.7113E−09 S10 0.0000E+00 −5.5236E−06 3.8284E−07 −7.6534E−09 S11 −4.3256E+01  −2.2796E−05 1.4432E−06 −3.3666E−08 S12 −1.5106E+01  −2.0799E−06 1.4161E−07 −3.2697E−09

TABLE 8 Wide Tele Fno 1.96 3.10 2ω (°) 47.21 24.65 f (mm) 9.261 18.525 Wide Tele Contracted TTL (mm) 19.600 19.600 8.383 LB (mm) 1.539 7.385 1.440 f1 (mm) −15.723 f2 (mm) 6.249 f3 (mm) −11.261 f4 (mm) 14.013 fG5 (mm) −16.384 f5 (mm) 24.692 f6 (mm) −9.715 IH (mm) 4.000 Zoom ratio 2.000

As shown in Table 21, Embodiment 2 satisfies the conditions (1) to (10).

FIG. 5 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 2 of the present disclosure. FIG. 6 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 2 of the present disclosure. It can be known that the zoom lens becomes miniature with TTL equal to 8.383 and becomes bright with Fno equal to 1.96 and has a zoom ratio equal to 2.000 at the wide angle end and has excellent optical performance as shown in FIG. 5 and FIG. 6 in Embodiment 2 of the present disclosure.

Embodiment 3

FIG. 7 is a schematic diagram of a structure of the zoom LA according to Embodiment 3 of the present disclosure. Table 9 shows the central curvature radiuses R of the object-side surfaces and the image-side surfaces of the zoom lens LA of the first lens L1 to the six lens L6, the on-axis thicknesses d of the lenses, the on-axis distances d between the lenses, the refractive indexes nd and the abbe numbers vd. Table 10 shows the values of A, B, C, D and E when contracted or photographing. Table 11 shows the conic coefficient k and the aspheric surface coefficients. Table 12 shows values of Fno, 2ω, f, TTL, LB, f1, f2, f3, f4, fG5, f5, f6, IH and zoom ratio.

TABLE 9 effective R d nd νd radius (mm) S1 R1 10.58008 d1 1.042 nd1 1.4959 ν1 81.655 4.784 S2 R2 4.52948 D12 d2 A 4.108 Stop ∞ d3 −1.107  3.177 S3 R3 5.07855 d4 2.168 nd2 1.5806 ν2 60.079 3.187 S4 R4 −8.45974 d5 B 3.062 S5 R5 16.45587 d6 0.400 nd3 1.6700 ν3 19.392 2.563 S6 R6 3.65515 d7 C 2.441 S7 R7 25.36114 d8 0.613 nd4 1.5438 ν4 56.029 2.530 S8 R8 −9.03460 d9 D 2.557 S9 R9 133.73082 d10 0.738 nd5 1.6700 ν5 19.392 3.429 S10 R10 −21.13099 d11 0.050 3.532 S11 R11 6.66943 d12 0.563 nd6 1.4959 ν6 81.655 3.551 S12 R12 3.24530 d13 0.410 3.791 S13 R13 ∞ d14 0.210 ndg 1.5168 νg 64.167 3.825 S14 R14 ∞ d15 E 3.848 Reference wavelength = 587.6 nm

TABLE 10 Photographing Wide Tele Contracted A 6.273 1.440 1.310 B 1.444 1.413 0.200 C 1.018 1.425 0.643 D 4.656 0.207 0.200 E 1.122 10.028 0.890

TABLE 11 Conic coefficient Aspheric surface coefficients k A4 A6 A8 A10 S1 0.0000E+00 −4.4095E−03 2.0708E−04 −3.9038E−06 −1.9264E−07 S2 0.0000E+00 −6.3328E−03 2.7470E−04 −1.7528E−05  1.1901E−06 S3 −3.6269E−01   4.9698E−04 9.1645E−06  5.8361E−06 −1.8648E−06 S4 0.0000E+00  5.7932E−03 −4.6315E−04   4.4802E−05 −4.1143E−06 S5 0.0000E+00 −1.0829E−02 3.3479E−03 −8.3487E−04  1.3433E−04 S6 −4.0285E+00  −1.4720E−02 4.4418E−03 −1.0849E−03  1.7666E−04 S7 0.0000E+00 −6.8090E−03 4.4941E−04  1.9025E−04 −5.2820E−07 S8 4.1694E+00  5.6632E−04 2.3946E−04  2.1157E−04 −1.1785E−05 S9 0.0000E+00  3.6015E−03 −2.2196E−03   8.3091E−04 −1.6445E−04 S10 0.0000E+00 −7.2986E−03 2.0443E−03  1.4646E−04 −9.7643E−05 S11 −7.2588E+00  −4.4240E−02 1.2333E−02 −1.9295E−03  1.8668E−04 S12 −7.5252E+00  −1.5700E−02 3.2886E−03 −4.7529E−04  4.0819E−05 Conic coefficient Aspheric surface coefficients k A12 A14 A16 S1 0.0000E+00  2.0604E−08 −7.4463E−10  9.9131E−12 S2 0.0000E+00 −8.9260E−08  4.3084E−09 −1.0036E−10 S3 −3.6269E−01   3.0197E−07 −2.3163E−08  7.0698E−10 S4 0.0000E+00  3.2966E−07 −1.9572E−08  6.0139E−10 S5 0.0000E+00 −1.3718E−05  8.2984E−07 −2.2114E−08 S6 −4.0285E+00  −1.9160E−05  1.2721E−06 −3.6712E−08 S7 0.0000E+00 −7.6718E−06  9.7243E−07 −4.1555E−08 S8 4.1694E+00 −1.0882E−06 −3.6653E−08  7.6618E−09 S9 0.0000E+00  1.7312E−05 −9.4394E−07  2.0940E−08 S10 0.0000E+00  1.2379E−05 −6.9673E−07  1.5505E−08 S11 −7.2588E+00  −1.2020E−05  4.7200E−07 −8.0207E−09 S12 −7.5252E+00  −2.0251E−06  5.3252E−08 −5.6470E−10

TABLE 12 Wide Tele Fno 1.94 3.06 2ω (°) 47.74 24.12 f (mm) 9.237 18.455 Wide Tele Contracted TTL (mm) 19.600 19.600 8.331 LB (mm) 1.742 10.648 1.510 f1 (mm) −16.937 f2 (mm) 5.808 f3 (mm) −7.102 f4 (mm) 12.327 fG5 (mm) −28.472 f5 (mm) 27.286 f6 (mm) −13.481 IH (mm) 4.000 Zoom ratio 1.998

As shown in Table 21, Embodiment 3 satisfies the conditions (1) to (10).

FIG. 8 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 3 of the present disclosure. FIG. 9 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 3 of the present disclosure. It can be known that the zoom lens becomes miniature with TTL equal to 8.331 and becomes bright with Fno equal to 1.94 and has a zoom ratio equal to 1.998 at the wide angle end and has excellent optical performance as shown in FIG. 8 and FIG. 9 in Embodiment 3 of the present disclosure.

Embodiment 4

FIG. 10 is a schematic diagram of a structure of the zoom LA according to Embodiment 4 of the present disclosure. Table 13 shows the central curvature radiuses R of the object-side surfaces and the image-side surfaces of the zoom lens LA of the first lens L1 to the six lens L6, the on-axis thicknesses d of the lenses, the on-axis distances d between the lenses, the refractive indexes nd and the abbe numbers vd. Table 14 shows the values of A, B, C, D and E when contracted or photographing. Table 15 shows the conic coefficient k and the aspheric surface coefficients. Table 16 shows values of Fno, 2ω, f, TTL, LB, f1, f2, f3, f4, fG5, f5, f6, IH and zoom ratio.

TABLE 13 Effective R d nd νd radius (mm) S1 R1 14.98234 d1 1.013 nd1 1.4959 ν1 81.655 4.634 S2 R2 5.26985 D12 d2 A 4.122 Stop ∞ d3 −1.047  3.153 S3 R3 5.04601 d4 2.161 nd2 1.5806 ν2 60.079 3.162 S4 R4 −9.92541 d5 B 3.081 S5 R5 5.74344 d6 0.400 nd3 1.6700 ν3 19.392 2.653 S6 R6 2.98243 d7 C 2.555 S7 R7 −32.32706 d8 0.589 nd4 1.5438 ν4 56.029 2.734 S8 R8 −7.62534 d9 D 2.712 S9 R9 17.33172 d10 0.759 nd5 1.6700 ν5 19.392 3.439 S10 R10 34.53207 d11 0.205 3.552 S11 R11 5.78882 d12 0.625 nd6 1.4959 ν6 81.655 3.559 S12 R12 3.30504 d13 0.390 3.810 S13 R13 ∞ d14 0.210 ndg 1.5168 νg 64.167 3.838 S14 R14 ∞ d15 E 3.860 Reference wavelength = 587.6 nm

TABLE 14 Photographing Wide Tele Contracted A 6.050 1.297 1.247 B 1.240 1.194 0.200 C 1.581 2.678 0.660 D 4.383 0.200 0.200 E 1.042 8.927 0.890

TABLE 15 Conic coefficient Aspheric surface coefficients k A4 A6 A8 A10 S1 0.0000E+00 −3.7536E−03 2.2036E−04 −1.0070E−05 4.2179E−07 S2 0.0000E+00 −5.1108E−03 2.7540E−04 −1.8794E−05 1.1984E−06 S3 −5.1704E−01   3.5277E−04 3.0334E−05 −9.5870E−06 2.3186E−06 S4 0.0000E+00  2.5600E−03 4.2044E−05 −4.4946E−05 8.1661E−06 S5 0.0000E+00 −3.3766E−02 8.2127E−03 −1.7569E−03 2.7773E−04 S6 −4.8937E+00  −2.2706E−02 7.0416E−03 −1.7633E−03 3.2056E−04 S7 0.0000E+00  4.7585E−04 6.9018E−04 −7.4376E−06 7.4010E−06 S8 −1.1589E+01   1.1854E−04 9.4606E−04 −7.7468E−06 1.1519E−06 S9 0.0000E+00  3.4171E−03 −1.3641E−03   4.1669E−04 −8.5975E−05  S10 0.0000E+00 −5.7698E−03 1.7512E−03 −1.8602E−04 −5.6310E−06  S11 −4.0247E+00  −4.3700E−02 1.0875E−02 −1.7947E−03 2.0457E−04 S12 −7.4985E+00  −1.8283E−02 4.0547E−03 −6.2900E−04 6.4181E−05 Conic coefficient Aspheric surface coefficients k A12 A14 A16 S1 0.0000E+00 −1.3804E−08 2.8803E−10 −2.7601E−12 S2 0.0000E+00 −6.1311E−08 1.9359E−09 −2.8147E−11 S3 −5.1704E−01  −3.3809E−07 2.5780E−08 −8.4890E−10 S4 0.0000E+00 −8.5217E−07 4.8947E−08 −1.2589E−09 S5 0.0000E+00 −2.8852E−05 1.7428E−06 −4.5614E−08 S6 −4.8937E+00  −3.7570E−05 2.5214E−06 −7.1912E−08 S7 0.0000E+00 −8.7561E−07 −1.0308E−07   1.0630E−08 S8 −1.1589E+01   1.9139E−06 −4.8498E−07   2.7389E−08 S9 0.0000E+00  9.3294E−06 −5.2187E−07   1.1906E−08 S10 0.0000E+00  2.2998E−06 −1.7674E−07   4.8751E−09 S11 −4.0247E+00  −1.5144E−05 6.1970E−07 −1.0232E−08 S12 −7.4985E+00  −4.0456E−06 1.3823E−07 −1.9138E−09

TABLE 16 Wide Tele Fno 1.96 3.10 2ω (°) 46.99 24.12 f (mm) 9.253 18.526 Wide Tele Contracted TTL (mm) 19.600 19.600 8.501 LB (mm) 1.642 9.527 1.490 f1 (mm) −16.979 f2 (mm) 6.084 f3 (mm) −9.831 f4 (mm) 18.198 fG5 (mm) −27.090 f5 (mm) 51.027 f6 (mm) −16.945 IH (mm) 4.000 Zoom ratio 2.002

As shown in Table 21, Embodiment 4 satisfies the conditions (1) to (10).

FIG. 11 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 4 of the present disclosure. FIG. 12 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 4 of the present disclosure. It can be known that the zoom lens becomes miniature with TTL equal to 8.501 and becomes bright with Fno equal to 1.96 and has a zoom ratio equal to 2.002 at the wide angle end and has excellent optical performance as shown in FIG. 11 and FIG. 12 in Embodiment 4 of the present disclosure.

Embodiment 5

FIG. 13 is a schematic diagram of a structure of the zoom LA according to Embodiment 5 of the present disclosure. Table 17 shows the central curvature radiuses R of the object-side surfaces and the image-side surfaces of the zoom lens LA of the first lens L1 to the six lens L6, the on-axis thicknesses d of the lenses, the on-axis distances d between the lenses, the refractive indexes nd and the abbe numbers vd. Table 18 shows the values of A, B, C, D and E when contracted or photographing. Table 19 shows the conic coefficient k and the aspheric surface coefficients. Table 20 shows values of Fno, 2ω, f, TTL, LB, f1, f2, f3, f4, fG5, f5, f6, IH and zoom ratio.

TABLE 17 effective R d nd νd radius (mm) S1 R1 14.54031 d1 0.932 nd1 1.5264 ν1 76.860 4.584 S2 R2 5.48677 D12 d2 A 4.128 Stop ∞ d3 −1.020  3.134 S3 R3 5.00546 d4 2.099 nd2 1.5264 ν2 76.860 3.144 S4 R4 −11.41165 d5 B 3.107 S5 R5 4.72445 d6 0.400 nd3 1.6700 ν3 19.392 2.680 S6 R6 2.80958 d7 C 2.648 S7 R7 −28.21289 d8 0.639 nd4 1.5438 ν4 56.029 2.747 S8 R8 −6.01316 d9 D 2.724 S9 R9 −35.22355 d10 0.847 nd5 1.6700 ν5 19.392 3.413 S10 R10 −11.12353 d11 0.050 3.516 S11 R11 6.55954 d12 0.725 nd6 1.5264 ν6 76.860 3.517 S12 R12 2.95172 d13 0.430 3.811 S13 R13 ∞ d14 0.210 ndg 1.5168 νg 64.167 3.843 S14 R14 ∞ d15 E 3.865 Reference wavelength = 587.6 nm

TABLE 18 Photographing Wide Tele Contracted A 6.028 1.271 1.221 B 2.355 2.272 0.200 C 1.155 1.876 0.680 D 3.713 0.200 0.200 E 1.037 8.668 0.890

TABLE 19 Conic coefficient Aspheric surface coefficients k A4 A6 A8 A10 S1 0.0000E+00 −3.4372E−03 1.9939E−04 −8.9861E−06 3.3833E−07 S2 0.0000E+00 −4.5696E−03 2.3843E−04 −1.4091E−05 6.7722E−07 S3 −6.1134E−01   1.2020E−04 4.7405E−05 −1.4912E−05 3.4106E−06 S4 0.0000E+00  1.5507E−03 −1.2703E−05  −2.3469E−06 2.9676E−07 S5 0.0000E+00 −2.9557E−02 4.9607E−03 −7.3211E−04 7.3824E−05 S6 −4.0488E+00  −1.8215E−02 3.6392E−03 −5.8151E−04 5.8514E−05 S7 0.0000E+00 −3.2762E−03 6.4781E−04 −1.1358E−04 7.8336E−05 S8 −8.8647E+00  −4.1463E−03 9.4507E−04  2.3621E−05 −3.4675E−06  S9 0.0000E+00  9.1110E−03 −2.6888E−03   6.0171E−04 −8.8958E−05  S10 0.0000E+00  8.4438E−03 −3.4629E−03   9.4445E−04 −1.3749E−04  S11 −5.7915E+00  −3.2471E−02 4.9171E−03 −3.0991E−04 9.4133E−07 S12 −6.7555E+00  −1.7289E−02 3.2197E−03 −4.1572E−04 3.5257E−05 Conic coefficient Aspheric surface coefficients k A12 A14 A16 S1 0.0000E+00 −9.3236E−09 1.6970E−10 −1.5497E−12 S2 0.0000E+00 −2.7519E−08 8.1238E−10 −1.2348E−11 S3 −6.1134E−01  −4.4619E−07 3.0616E−08 −8.9323E−10 S4 0.0000E+00 −6.9638E−08 8.0230E−09 −3.6431E−10 S5 0.0000E+00 −5.1003E−06 2.6712E−07 −8.2591E−09 S6 −4.0488E+00  −3.4616E−06 1.3256E−07 −2.9525E−09 S7 0.0000E+00 −1.2556E−05 7.3534E−07 −1.3887E−08 S8 −8.8647E+00   6.8276E−06 −1.2375E−06   5.8817E−08 S9 0.0000E+00  7.5377E−06 −3.4555E−07   6.7229E−09 S10 0.0000E+00  1.0482E−05 −4.1404E−07   6.8885E−09 S11 −5.7915E+00   4.1863E−07 3.3193E−09 −4.5789E−10 S12 −6.7555E+00  −1.9038E−06 5.7222E−08 −6.9007E−10

TABLE 20 Wide Tele Fno 1.96 3.13 2ω (°) 46.73 23.91 f (mm) 9.254 18.635 Wide Tele Contracted TTL (mm) 19.600 19.600 8.503 LB (mm) 1.677 9.308 1.530 f1 (mm) −17.356 f2 (mm) 6.914 f3 (mm) −11.292 f4 (mm) 13.911 fG5 (mm) −21.439 f5 (mm) 23.926 f6 (mm) −10.954 IH (mm) 4.000 Zoom ratio 2.014

As shown in Table 21, Embodiment 5 satisfies the conditions (1) to (10).

FIG. 14 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the wide angle end according to Embodiment 5 of the present disclosure. FIG. 15 is a schematic diagram showing longitudinal spherical aberrations, astigmatic field curves and distortions of the zoom lens LA at the telephoto end according to Embodiment 5 of the present disclosure. It can be known that the zoom lens becomes miniature with TTL equal to 8.503 and becomes bright with Fno equal to 1.96 and has a zoom ratio equal to 2.014 at the wide angle end and has excellent optical performance as shown in FIG. 14 and FIG. 15 in Embodiment 5 of the present disclosure.

Table 21 shows various parameters of Embodiments 1, 2, 3, 4 and 5 and values corresponding to the parameters specified in the above conditions (1) to (10).

TABLE 21 Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Memo f_Tele/f_Wide 2.000 2.000 1.998 2.002 2.014 Condition (1) f3/f2 −1.391 −1.802 −1.223 −1.616 −1.633 Condition (2) f4/f2 2.012 2.242 2.123 2.991 2.012 Condition (3) f1/f2 −3.183 −2.516 −2.916 1.727 −2.510 Condition (4) fG5/f2 −3.435 −2.622 −4.903 −4.452 −3.101 Condition (5) f5/f6 −2.196 −2.542 −2.024 −3.011 −2.184 Condition (6) LB_Tele/LB_Wide 6.191 4.799 6.111 5.802 5.551 Condition (7) ν1 81.655 81.655 81.655 81.655 76.860 Condition (8) ν2 60.079 60.079 60.079 60.079 76.860 Condition (9) ν6 81.655 81.655 81.655 81.655 76.860 Condition (10)

It will be understood by those of ordinary skill in the art that the embodiments described above are specific embodiments realizing the present disclosure, and that in practical applications, various changes may be made thereto in form and in detail without departing from the range and scope of the disclosure. 

What is claimed is:
 1. A zoom lens comprising, from an object side to an image side in sequence: a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, a fifth lens group having a negative refractive power; wherein distances between adjacent two of the first lens, the second lens, the third lens, the fourth lens and the fifth lens group are variable in the direction of an optical axis; the fifth lens group comprises a fifth lens having a positive refractive power and a sixth lens having a negative refractive power; the zoom lens satisfies conditions of: f_Tele/f_Wide>1.8;  (1) −1.85≤f3/f2≤−1.20; and  (2) 2.00≤f4/f2≤3.00;   (3) where f_Wide denotes a focal length of the zoom lens at the wide angle end; f_Tele denotes a focal length of the zoom lens at the telephoto end; f2 denotes a focal length of the second lens; f3 denotes a focal length of the third lens; and f4 denotes a focal length of the fourth lens.
 2. The zoom lens according to claim 1, wherein the zoom lens further satisfies a condition of: −3.20≤f1/f2≤−2.50;  (4) where f1 denotes a focal length of the first lens; and f2 denotes a focal length of the second lens.
 3. The zoom lens according to claim 1, wherein the zoom lens further satisfies a condition of: −5.00≤fG5/f2≤−2.50; and   (5) −3.10≤f5/f6≤−2.00;  (6) where f2 denotes a focal length of the second lens; fG5 denotes a combined focal length of the fifth lens group; f5 denotes a focal length of the fifth lens; and f6 denotes a focal length of the sixth lens.
 4. The zoom lens according to claim 1, wherein the zoom lens further satisfies a condition of: 4.78≤LB_Tele/LB_Wide≤6.20;  (7) where LB_Wide denotes an on-axis distance from an image-side surface of the sixth lens to an image surface at the wide angel end; and LB_Tele denotes an on-axis distance from an image-side surface of the sixth lens to an image surface at the telephoto end.
 5. The zoom lens according to claim 1, wherein the zoom lens further satisfies a condition of: 76.00≤v1≤82.00;  (8) 58.00≤v2≤78.00; and  (9) 76.00≤v6≤82.00;  (10) where v1 denotes an abbe number of the first lens L1; v2 denotes an abbe number of the second lens L2; and v6 denotes an abbe number of the sixth lens L6. 